U.S. patent application number 13/129392 was filed with the patent office on 2011-11-24 for crlh-tl meta material antenna.
Invention is credited to Jeong Keun Jl, Byung Hoon Ryou, Won Mo Sung.
Application Number | 20110285602 13/129392 |
Document ID | / |
Family ID | 42170511 |
Filed Date | 2011-11-24 |
United States Patent
Application |
20110285602 |
Kind Code |
A1 |
Ryou; Byung Hoon ; et
al. |
November 24, 2011 |
CRLH-TL META MATERIAL ANTENNA
Abstract
There is provided an antenna having a spiral-shaped loading
formed on the ground plane, in which a resonant frequency is
lowered as the reactance component of a CRLH-TL structure is
adjusted.
Inventors: |
Ryou; Byung Hoon; (Seoul,
KR) ; Sung; Won Mo; (Gyeonggi-do, KR) ; Jl;
Jeong Keun; (Seoul, KR) |
Family ID: |
42170511 |
Appl. No.: |
13/129392 |
Filed: |
November 11, 2009 |
PCT Filed: |
November 11, 2009 |
PCT NO: |
PCT/KR2009/006606 |
371 Date: |
August 5, 2011 |
Current U.S.
Class: |
343/848 |
Current CPC
Class: |
H01Q 9/27 20130101; H01Q
1/48 20130101; H01Q 21/30 20130101; H01Q 15/0086 20130101; H01Q
13/10 20130101 |
Class at
Publication: |
343/848 |
International
Class: |
H01Q 1/48 20060101
H01Q001/48 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2008 |
KR |
10-2008-0112576 |
Claims
1. An antenna having a spiral-shaped loading formed on a ground
plane, for lowering a resonant frequency by adjusting reactance
components of a CRLH-TL structure.
2. The antenna according to claim 1, wherein the spiral loading
lowers a 0-th order resonant frequency if inductance of a parallel
inductor L.sub.L is increased in the CRLH-TL structure.
3. The antenna according to claim 1, wherein the spiral loading is
formed as a spiral-shaped slot.
4. The antenna according to claim 1, wherein the resonant frequency
is lowered as the number of turns of spiral is increased.
5. The antenna according to claim 4, wherein if the spiral loading
is configured with two cells and both of the two cells are formed
clockwise, a -1-th order resonant frequency and a 0-th order
resonant frequency are lowered as the number of turns of spiral is
increased.
6. The antenna according to claim 4, wherein if the spiral loading
is configured with two cells respectively formed clockwise and
counterclockwise to face each other, a -1-th order resonant
frequency and a 0-th order resonant frequency are lowered as the
number of turns of spiral is increased.
7. The antenna according to claim 1, wherein performance is
adjusted depending on changes in the number of unit cells and sizes
of a patch, a via, and a dielectric substrate constructing the
spiral loading, and a width, an interval, and a direction of the
spiral loading, and a position and method of feeding power to the
spiral loading.
8. The antenna according to claim 7, wherein the dielectric
substrate is placed in a middle, a power feed line and two patches
are placed on an upper layer, the patches on the upper layer is
connected to the spiral loadings on a lower layer through the vias,
and the ground plane where the spiral-shaped slots are formed is
placed on the lower layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a composite right and left
handed transmission line (CRLH-TL) meta material antenna, and more
specifically, to a CRLH-TL meta material antenna miniaturized using
spiral loadings of a ground plane.
BACKGROUND ART
[0002] A meta material structure attracting attention recently in
the electromagnetic wave application field shows a peculiar
phenomenon that has not been mentioned in the general
electromagnetic theory. Since the meta material structure has
symbols of diverse group velocities and phase velocities in the
dispersion characteristic, propagation of electrons is explained in
the left-hand propagation law, not in the right-hand propagation
law. For example, when an electromagnetic wave propagates through a
meta material in a free space, the transverse components of a
transmitted wave are reverse to those of an incident wave, and if a
right-handed transmission line (RH-TL) is combined with a
left-handed transmission line (LH-TL), pass and stop bands are
formed to be different from those of only a conventional RH-TL.
DISCLOSURE OF INVENTION
Technical Problem
[0003] Therefore, the present invention has been made in view of
the above problems, and it is an object of the present invention to
provide a CRLH-TL meta material antenna miniaturized using spiral
loadings of a ground plane.
Technical Solution
[0004] An antenna according to an embodiment of the present
invention is implemented using spiral-shaped loadings on a ground
plane, and thus a resonant frequency is lowered as the reactance
components of a CRLH-TL stricture are adjusted.
Advantageous Effects
[0005] According to the present invention, a miniaturized antenna
implemented using spiral-shaped loadings on a ground plane can be
provided by obtaining a low resonant frequency as the reactance
components of a CRLH-TL stricture are adjusted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a view showing an equivalent circuit and a unit
cell of a CRLH-TL structure.
[0007] FIG. 2 is a view showing a propagation-constant vs.
frequency graph according a circuit of a CRLH-TL structure.
[0008] FIG. 3 is a view showing a CRLH-TL antenna implemented using
two unit cells according to an embodiment of the present invention,
in which the CRLH-TL antenna is divided into layers.
[0009] FIG. 4 is a top view of a LH-TL antenna implemented using
two unit cells according to an embodiment of the present invention,
in which patches and a power feed line are shown.
[0010] FIG. 5 is a bottom view a CRLH-TL antenna implemented using
two unit cells according to an embodiment the present invention, in
which spiral loadings are implemented along spiral-shaped
slots.
[0011] FIG. 6 is a view showing return losses according to the
number of turns of spiral when both of spiral loadings of two cells
are implemented clockwise.
[0012] FIG. 7 is a view showing a gain distribution or a radiation
pattern of a 0-th order resonant frequency when the number of turns
is three in FIG. 6.
[0013] FIG. 5 is a view showing return losses according to the
number of turns of spiral when spiral loadings of two cells are
implemented to face each other.
[0014] FIG. 9 is a view showing a gain distribution or a radiation
pattern of a 0-th order resonant frequency when the number of turns
is three in FIG. 8.
BEST MODE FOR CARRYING OUT THE INVENTION
[0015] A CRLH-TL meta material antenna will be hereafter described
in detail, with reference to the accompanying drawings.
[0016] FIG. 1 is a view showing an equivalent circuit and a unit
cell of a CRLH-TL structure.
[0017] Referring to FIG. 1, the equivalent circuit 100 of a CRLH-TL
structure comprises a serial inductor L.sub.R, a parallel capacitor
C.sub.R, a parallel inductor L.sub.L, and a serial capacitor
C.sub.L, and includes a unit cell 110. Here, the serial inductor
L.sub.R and the parallel capacitor C.sub.R are shown in order to
equalize a circuit of a general structure, and the parallel
inductor L.sub.L and the serial capacitor C.sub.L are added to
equalize a circuit of the CRLH-TL structure.
[0018] The CRLH-TL structure is a typical structure of a meta
material applied to an antenna according to the present invention,
and this structure has a negative order (-) resonant mode, as well
as a positive order (+) resonant mode that can be seen in a
conventional antenna.
[0019] There is a 0-th order resonant mode where the propagation
constant becomes 0 among resonant modes of the CRLH-TL structure.
In the 0-th order resonant mode, a wavelength grows to be infinite,
and phase delay related to wave transmission does not occur. Since
reactance components constituting the CRLH-TL determine a resonant
frequency of the 0-th order resonant mode, the resonant frequency
is not affected by the length of an antenna, and thus it is
advantageous in miniaturizing the antenna.
[0020] Since an antenna according to an embodiment of the present
invention implements spiral-shaped loadings on a ground plane, a
low resonant frequency is obtained by adjusting the reactance
components, and thus the antenna can be miniaturized.
[0021] As described above, since the 0-th order resonant frequency
is determined by the reactance components, a spiral loading
increases inductance of the parallel inductor L.sub.L, and thus the
0-th order resonant frequency can be lowered in an antenna
according to the present invention.
[0022] FIG. 2 is a view showing a propagation-constant vs.
frequency graph according to a circuit of a CRLH-TL structure.
[0023] Referring to FIG. 2, in an antenna using a CRLH-TL structure
according to an embodiment of the present invention, the resonant
frequency varies depending on RH or LH region, and a 0-th or
negative order (-) resonant frequency, as well as a positive order
(+) resonant frequency, can be obtained.
[0024] FIG. 3 is a view showing a CRLH-TL antenna implemented using
two unit cells according to an embodiment of the present invention,
in which the CRLH-TL antenna is divided into layers.
[0025] Referring to FIG. 3, the CRLH-TL antenna 300 according to an
embodiment of the present invention is implemented using two unit
cells.
[0026] For example, in the CRLH-TL antenna 300 according to an
embodiment of the present invention, a dielectric substrate having
a permittivity of 2.2 and a dimension of 55 mm.times.55
mm.times.1.5 mm is placed in the middle, and a power feed line 351
having a width of 8 mm and two patches 321 and 322 having a size of
12.4 mm.times.25 mm are placed on the upper layer 311.
[0027] In addition, in the CRLH-TL antenna 300 according to an
embodiment of the present invention, the distance between the
patches 331 and 332 is 0.2 mm, and a ground plane on which
spiral-shaped slots having a width of 0.2 mm and an interval of 0.2
mm are implemented may be placed on the lower layer 312.
[0028] In addition, in the CRLH-TL antenna 300 according to an
embodiment of the present invention, the patches 321 and 322 of the
upper layer can be connected to spiral loadings 341 and 342 of the
lower layer through vias 331 and 332 having a radius of 0.2 mm.
[0029] Like this, in the CRLH-TL antenna 300 according to an
embodiment of the present invention, the spiral loadings are
implemented along the spiral-shaped slots.
[0030] FIG. 4 is a top view of a CRLH-TL antenna implemented using
two unit cells according to an embodiment of the present invention,
in which patches and a power feed line are shown, and FIG. 5 is a
bottom view of a CRLH-TL antenna implemented using two unit cells
according to an embodiment of the present invention, in which
spiral loadings are implemented along spiral-shaped slots.
[0031] FIG. 6 is a view showing return losses according to the
number of turns of spiral when both of spiral loadings of two cells
are implemented clockwise.
[0032] Referring to FIG. 6, in the antenna according to an
embodiment of the present invention, both of the spiral loadings of
the two unit cells are implemented in the same clockwise direction,
and it is understood that a -1-th order resonant frequency and a
0-th order resonant frequency are lowered as the number of turns of
spiral is increased for each of the spiral loadings.
[0033] FIG. 7 is a view showing a gain distribution or a radiation
pattern of a 0-th order resonant frequency when the number of turns
is three in FIG. 6.
[0034] In the antenna according to an embodiment of the present
invention, if the number of turns of spiral is three at the spiral
loading of a unit cell as shown in FIG. 6, the maximum gain for the
0-th order resonant frequency may be 0.03 dBi.
[0035] FIG. 8 is a view showing return losses according to the
number of turns of spiral when spiral loadings of two cells are
implemented to face each other.
[0036] Referring to FIG. 8, in the antenna according to an
embodiment of the present invention, the spiral loadings of the
first and second cells of the two unit cells are respectively
implemented clockwise and counterclockwise to face each other, and
it is understood that the -1-th order resonant frequency and the
0-th order resonant frequency are lowered as the number of turns
increases for each of the spiral loadings.
[0037] FIG. 9 is a view showing a gain distribution or a radiation
pattern of a 0-th order resonant frequency when the number of turns
is three in FIG. 8.
[0038] In the antenna according to an embodiment of the present
invention, if the number of turns of spiral is three at the spiral
loading of a unit cell as shown in FIG. 8, the maximum gain for the
0-th order resonant frequency may be -1.75 dBi.
[0039] In addition, in the antenna according to an embodiment of
the present invention, a user may obtain desired antenna
performance depending on changes in the number of unit cells, the
sizes of a patch, a via, and a dielectric substrate, the width,
interval, direction, and number of turns of the spiral loading, the
position and method of power feeding, and the like.
[0040] Like this, in the antenna according to an embodiment of the
present invention, spiral-shaped loadings are implemented on the
ground plane, and the reactance components of the CRLH-TL structure
are adjusted. Therefore, a low 0-th order resonant frequency or a
negative order resonant frequency is obtained regardless of the
length of the antenna, and thus miniaturization of the antennas can
be accomplished.
[0041] While the present invention has been described with
reference to the particular illustrative embodiments, it is not to
be restricted by the embodiments but only by the appended claims.
It is to be appreciated that those skilled in the art can change or
modify the embodiments without departing from the scope and spirit
of the present invention.
* * * * *